MC10H640_16 Datasheet, PDF (1/8 Pages) ON Semiconductor – PECL to TTL Clock Driver

MC10H640
68030/040 PECL to TTL
Clock Driver
Description
The MC10H640 generates the necessary clocks for the 68030,
68040 and similar microprocessors. It is guaranteed to meet the clock
specifications required by the 68030 and 68040 in terms of part-to-part
skew, within-part skew and also duty cycle skew.
The user has a choice of using either TTL or PECL (ECL referenced
to +5.0 V) for the input clock. TTL clocks are typically used in present
MPU systems. However, as clock speeds increase to 50 MHz and
beyond, the inherent superiority of ECL (particularly differential
ECL) as a means of clock signal distribution becomes increasingly
evident. The H640 also uses differential PECL internally to achieve its
superior skew characteristic.
The H640 includes divide-by-two and divide-by-four stages, both to
achieve the necessary duty cycle skew and to generate MPU clocks as
required. A typical 50 MHz processor application would use an input
clock running at 100 MHz, thus obtaining output clocks at 50 MHz
and 25 MHz (see Logic Diagram).
Features
• Generates Clocks for 68030/040
• Meets 030/040 Skew Requirements
• TTL or PECL Input Clock
• Extra TTL and PECL Power/Ground Pins
• Asynchronous Reset
• Single +5.0 V Supply
• This Device is Pb-Free, Halogen Free and is RoHS Compliant
Function
Reset (R): LOW on RESET forces all Q outputs LOW and all Q
outputs HIGH.
Power-Up: The device is designed to have the POS edges of the ÷ 2
and ÷ 4 outputs synchronized at power up.
Select (SEL): LOW selects the ECL input source (DE/DE). HIGH
selects the TTL input source (DT).
The H640 also contains circuitry to force a stable state of the ECL
input differential pair, should both sides be left open. In this case, the
DE side of the input is pulled LOW, and DE goes HIGH.
www.onsemi.com
PLLC−28
FN SUFFIX
CASE 776−02
MARKING DIAGRAM*
1
MC10H640G
AWLYYWW
A
= Assembly Location
WL = Wafer Lot
YY
= Year
WW = Work Week
G
= Pb-Free Package
*For additional marking information, refer to
Application Note AND8002/D.
ORDERING INFORMATION
Device
MC10H640FNG
Package
PLLC−28
(Pb-Free)
Shipping
37 Units / Tube
© Semiconductor Components Industries, LLC, 2006
1
August, 2016 − Rev. 9
Publication Order Number:
MC10H640/D